在React中过滤列表

Question

我正在使用Flux + React Router + Firebase创建一个基本博客.我无法尝试获取单个博客文章进行渲染.当我点击指向单个帖子的链接时,我会尝试从所有帖子列表中过滤掉所有其他帖子,并仅显示我的firebase数据库中的一个帖子.

我尝试通过将firebase条目的键与url params匹配来完成此操作if (this.props.routeParams.key===key).我真的不知道为了实现这一点我必须做些什么.欢迎任何建议.

下面是Blogger.jsx,我允许用户创建博客帖子的页面,然后在博客文章下方,我显示所有博客帖子的标题列表.

import AltContainer from 'alt-container';
import React from 'react';
import { Link } from 'react-router';
import List from './List.jsx'
import Firebase from 'firebase'
import BlogStore from '../stores/BlogStore'
import BlogActions from '../actions/BlogActions';


const rootURL = 'https://incandescent-fire-6143.firebaseio.com/';



export default class Blogger extends React.Component {
  constructor(props) {
    super(props);
    BlogStore.getState();
    BlogStore.mountFirebase();
    {console.log(this.props.location.query)}

    };


  componentDidMount() {
    BlogStore.listen((state) => {
      this.setState(state)
    })
    this.firebaseRef = new Firebase(rootURL + 'items/');
  }

  componentWillMount() {
    BlogStore.unlisten((state) => {
      this.setState(state)
    })
  }




  renderList = (key) => {
      return (
      <Link to={`blogshow/${key}`}> <List key={key} blog={this.state.blog[key]} /> </Link>
      )
    }


  handleInputChange = () => {

    BlogStore.setState({
      title: this.refs.title.value,
      text: this.refs.text.value});
  }


  handleClick = () => {

    BlogStore.handleClick();
  }


  render() {
    return (
      <div>
        <div className="row panel panel-default">
          <div className="col-md-8 col-md-offset-2">
            <h2>
                Create a New Blog Post
            </h2>
          </div>
        </div>

<h2>Blog Title</h2>
        <div className="input-group">
          <input
          ref="title"
          value={BlogStore.state.title}
          onChange = {this.handleInputChange}
          type="text"
          className="form-control"/>
          <span className="input-group-btn">

          </span>
        </div>

<h2>Blog Entry</h2>
        <div className="input-group">
          <textarea
          ref="text"
          value={BlogStore.state.text}
          onChange = {this.handleInputChange}
          type="text"
          className="form-control"/>

        </div>

        <div className="blog-submit input-group-btn">
          <button onClick={this.handleClick}
          className="btn btn-default" type="button">
            Publish Blog Post
          </button>
        </div>

        {/*<List blog={this.state.blog} />*/}

        {Object.keys(BlogStore.state.blog)
       .map(this.renderList)}



    </div>



    );
  }

}

当用户单击指向单个博客帖子的链接时,应将其传输到仅显示该单个博客帖子的页面.我把这个组件称为BlogShow.我无法让BlogShow呈现,因为我一直在收到错误

invariant.js？4599:45 Uncaught Invariant Violation:BlogShow.render():必须返回一个有效的React元素(或null).您可能已返回undefined,数组或其他一些无效对象.

这是BlogShow.jsx:

import AltContainer from 'alt-container';
import React from 'react';
import { Link } from 'react-router';
import Blogger from './Blogger'
import List from './List'
const rootURL = 'https://incandescent-fire-6143.firebaseio.com/';

import BlogStore from '../stores/BlogStore'
import BlogActions from '../actions/BlogActions';



export default class BlogShow extends React.Component {
  constructor(props) {
    super(props);
    {console.log(this.props.routeParams.key)}
    this.filterList = this.filterList.bind(this);

}



filterList(key) {
  if (this.props.routeParams.key===key) {
    return (<List key={key} blog={BlogStore.state.blog[key]} />)
  }
}

  render() {

             <div> {Object.keys(BlogStore.state.blog).map(this.filterList)} </div>


  }

}

Answer 1

您收到该错误,因为您的Component BlogShow没有返回任何内容.

render() {
    <div> {Object.keys(BlogStore.state.blog).map(this.filterList)} </div>
}

应该:

render() {
    return <div> {Object.keys(BlogStore.state.blog).map(this.filterList)} </div>
}